The strength reduction factor of compression-controlled tied columns is _____.

Designers should compute the interaction diagram for the most favorable bar orientation in a circular column because they have little to no control over how the bars are actually installed.

Compression members in concrete structures are subjected to only axial loads.

Determine the maximum axial strength φPn,max for the following circular spiral column.Column diameter, h = 26 in.Number of longitudinal bars = 10Size of longitudinal bars = No. 10Size of spirals = No. 3Concrete strength = 7,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of spirals = 60,000 psi

To account for the effect of accidental moments, the ACI Code specifies that the maximum load on a column must not exceed 0.85 times the axial-load capacity of tied columns and 0.8 times the axial-load capacity of spiral columns.

Compression-controlled tied columns have a strength-reduction factor of _____.

Determine the maximum axial strength φPn,max for the following circular tie column.Column diameter, h = 28 in.Number of longitudinal bars = 8Size of longitudinal bars = No. 6Size of ties = No. 4Concrete strength = 2,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 60,000 psi

In a typical construction cycle, the reinforcement and concrete for the beams and slabs in a floor system are placed before the reinforcement and concrete for the columns below it.

Determine the maximum axial strength φPn,max for the following circular spiral column.Column diameter, h = 26 in.Number of longitudinal bars = 8Size of longitudinal bars = No. 10Size of spirals = No. 4Concrete strength = 6,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of spirals = 60,000 psi

In nonseismic areas, spiral columns are used more extensively.